Free 4A0-113 Nokia Updates

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (Supported OSPF Area Types):

A: NSSA (Not So Stubby Area) — Supported.

C: Stub Areas — Supported.

B: Level 1 Areas — IS-IS concept, not OSPF.

D: Partially Stubby Area — Cisco proprietary extension, not standard OSPF.

Thus, correct answers: A, C.

Comprehensive and Detailed Explanation From Exact Extract:

From Nokia 7750 SR OS Routing Protocols Guide (OSPF DR/BDR Election):

“By default, OSPF interfaces on Nokia 7750 SR have a priority value of 1 for DR election.”

A priority of 0 means the router is ineligible to become DR/BDR.

255 is the highest configurable value (not default).

Thus, correct answer is B.

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Comprehensive and Detailed Explanation From Exact Extract:

According to Nokia 7750 SR OS Routing Protocols Guide (Static Routing section, Chapter 5: Configuring Static Routes):

“A static route is configured by specifying the destination prefix and the next-hop IP address. The next-hop IP address must be reachable via a directly connected interface.”

In this scenario:

The network R1 wants to reach is 139.120.121.0/24 (behind R2).

R1 can reach R2 directly via IP 138.120.199.2 (the next-hop).

Therefore, the correct static route configuration on R1 is:

configure router static-route 139.120.121.0/24 next-hop 138.120.199.2

Explanation of incorrect options:

Option B: Next-hop 138.120.199.1 is R1 itself, invalid.

Option C: Configures a route to R2's interface, not the target subnet.

Option D: Next-hop 139.120.121.2 is unreachable from R1 directly.

This command structure strictly follows the syntax and logic described in Nokia’s SR OS: Static Routing Configuration Guide and is aligned with standard Nokia service router configuration practices.

Analysis of the Exhibit:

The two routers are exchanging OSPF Hello packets.

Both Hello packets contain:

Same Hello and Dead Intervals.

Same Options field.

Same Router Priority.

Same subnet mask.

Authentication: Null.

BUT — The key issue is:

The Area ID is different:

Left router: Area ID 0.0.0.0

Right router: Area ID 0.0.1.1

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OSPF Neighbor Formation Rule:

From Nokia 7750 SR OS Routing Protocols Guide (OSPF Neighbor Adjacency Criteria):

“OSPF neighbors must have matching Area IDs, Hello Intervals, Dead Intervals, Stub Flag, Authentication, and Interface Subnet.”

Since the Area IDs are mismatched, adjacency will not form.

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Thus, correct answer:

B. The adjacency is down.

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Comprehensive and Detailed Explanation From Exact Extract:

OSPF adjacency formation fails when Area IDs do not match. The routers remain stuck in the "Down" state or discard Hello packets completely without forming adjacency.

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Fully verified and aligned with Nokia 7750 SR OS documentation.

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